<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="js/vue.js"></script>
</head>
<body>
    <!-- v-once 界面不会跟随改变 该指令表示元素和组件只被渲染一次 -->
    <div id="app">
        <h1 v-once>{{message}}</h1>
        
    </div>
    <script>
        let vm = new Vue({
            el:"#app",
            data:{
                message:'Hello CoderWhy'
            }
        })
    </script>
</body>
</html>